Jealousy is the colour of Kryptonite
by Kassebaum
Summary: Lena jumps to conclusions when she sees Kara with another woman.


This was based on a Tumblr post I saw. Let me know what you think!

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Lena stood in the middle of her office unable to move; fear rooting her to the spot. For someone who had spent their entire life hiding and subduing their true emotions she found herself unable to arrange her features into the mask she was so used to wearing, the mask she had perfected over many years to the point that even she was sometimes unable to tell the difference between being Lena and being a Luthor. The two blurred together until only the cold disdainful looks remained.

Until _she_ came along.

Kara _fucking_ Danvers.

That's who was in her office, who caused her mask to slip, who made her not play at being a Luthor, who made her heart skip a beat, who brought sunshine into her otherwise achromatic world.

Who was just standing in her office _laughing._ At her…

 _A few weeks earlier…_

Lena had been drawn to her the minute she had stepped foot in her office, the smile, the optimism, the way she fiddled with the sleeve on her cardigan when the smirk Lena levelled at her made her nervous.

Kara had retained eye contact a smidge longer than most people could manage when confronted with a flirting Lena Luthor and it intrigued her. The shy and flustered demeanour appeared to be an act; Lena saw the strength and determination in Kara's blue eyes and felt she had finally met someone who could truly challenge her.

Their meetings continued; flirtatious looks, lingering fingers on arms, but neither of them willing to step over the invisible unspoken line, neither willing to push for more.

Until Lena realised it was too late.

It was ridiculous really to think that Kara was single, that someone's world did not revolve around the brightest human being Lena had ever met. Of course she was the light of someone else's life.

She had first seen Kara and the short haired woman walking arm in arm through the restaurant district one evening through the window from where she was dining alone. They were giggling at some kind of joke, Kara playfully pushing on the other woman's shoulder before resting her head on it. The two women were in perfect sync, an ease about them that only came with knowing someone completely.

Lena was not prepared for the flurry of emotions that assaulted her.

She was angry; angry that Kara had seemingly led her to believe something could happen between them, despite never expressly saying so.

Lena was upset; upset that she had let herself believe that a woman as amazing and as pure as Kara could want her.

And Lena was jealous; jealous of the cute brunette who was touching _her_ Kara. That this woman knew everything about Kara; what made her laugh, what her favourite food was, whether she was a dog or a cat person. Lena wanted to be that person.

She shook it off, told herself she was reading too much into things. Lena knew that relationships existed between friends that were incredibly close, that could be mistaken for something else. Not that she had ever experienced it.

She was too proud to ask Kara if she was single, too much of a Luthor to admit that she wanted to know.

The next time she saw them Lena wasn't able to dismiss it as easily. Kara had come to to interview her about her _mother_ of all things. The flirting continued; the stolen glances Kara threw Lena when she thought she wasn't looking, the way Kara told Lena her mother must be proud of her made her melt.

She felt sure she had read the situation between Kara and this other woman incorrectly. Kara didn't seem like the type of person to flirt that obviously while in a relationship. Lena's heart soared.

As she left, Kara had pulled a tiny cactus out of her bag and popped it onto Lena's desk, explaining that it was a thank you for being her only good source in National City and that her office needed a bit of plant life. Lena snorted. _Actually snorted_. The sound her mother had trained out of her, deeming it unladylike, expelled itself from her mouth before she could stop it. Kara Danvers was tearing down her carefully and meticulously built walls.

However, Lena then watched from her office window with a sense of dread as Kara practically skipped towards the motorcycle that was waiting on the curb. The leather clad rider removed her helmet to reveal the same beaming brunette Lena had previously seen Kara with. She watched as Kara threw her arms round the nameless woman and pressed her lips against her cheek.

Lena felt her stomach drop and her teeth clench as Kara put on the pink helmet that was obviously hers and climbed onto the back of the motorcycle, wrapping her arms round the waist of mystery woman.

She threw the cactus in the trash on the way out of her office.

The third time gave her undeniable evidence; she had gone to Kara's apartment to request a meeting with Supergirl. The apartment had been so _Kara_ ; spacious and light, floral patterns decorating the furniture. It was somewhere to call home, a stark contrast to her own sparse monochromatic penthouse.

It was the little details that weren't Kara's influence that drew Lena's eye however; the biker boots by the front door and the leather jacket thrown over the back of a chair, they definitely weren't Kara's. The dishes waiting to be washed in the kitchen indicating the obvious: that two people had shared dinner last night. And the pictures, the pictures that depicted Kara's life with the same dark haired woman, placed lovingly around the apartment.

She left Kara's feeling like she had been punched in the stomach. She hated this other woman, the woman whose life was entwined with Kara's. Jealousy raged through her body, and she was unable to suppress the images flashing though her mind, images of the happy life they obviously shared.

Lena didn't want to know anything about this woman. It was easier to hate her if she remained nameless, just the woman she longed to be.

The very next day Lena learnt the name of the woman; Alex. Supergirl had yelled it out when Alex was taken hostage by the man her brother had sent to kill her.

Lena didn't register anything else as she shot him twice in the back, her mask perfectly in place as she stared at the women who had entranced _her_ Kara. An agent of some kind if the way she had fought her captor was anything to go by.

She managed a curt nod in the direction of this _Alex,_ then turned and fled the scene.

She didn't stick around to hear the shouts of _Agent_ _Danvers_ as the rest of her team caught up with her.

She didn't stick around because she didn't want Kara to see the tears in her eyes due to the heartache of knowing the name of the woman she was so desperate to be.

However, the CEO soon found that she couldn't keep away from Kara; she wanted to be in her life, even if that meant a constant knot in her stomach, so she found herself at CatCo to invite Kara to the gala she was hosting.

The smile on Kara's face when she saw Lena made her heart skip a beat, she was sure it was mirrored on her own face. Their eyes met and Lena felt herself get drawn in, drawn into whatever game it was Kara was playing with her heart.

Lena found herself so responsive to the blonde, her eyes lighting up, biting her lip. She had never been this physically expressive with anyone before.

She suddenly spotted the picture of Kara and Alex sitting on Kara's desk and it brought her back to earth with a thud. It was the same picture from _their_ apartment; the two of them smiling, arms wrapped round each other, looks of utter contentment across both of their faces. Lena felt her demeanour immediately shift, her cold persona shifting swiftly into place as she politely asked if Kara wanted to bring her _partner._ She couldn't bring herself to say girlfriend. Lena saw a quick look of confusion flash across Kara's face, but they were interrupted by some intern she can't even remember the name of (possibly Mark?) before she could push further. Kara fiddled nervously with the sleeve of her cardigan as she accepted the invitation for both herself and… Matt?

The gala had been a disaster, disarming an alien bomb planted under the stage the band was playing on was not something she had planned on doing. She had hardly spent any time with Kara. The only glimpse of hope had been that Kara had turned up without Alex; however that didn't mean anything Lena decided, she was probably working.

Lena began to resign herself to the fact that she would never be in Kara's life as anything more than a friend.

The attack on happened a few nights later. Lena was in the lobby when a black ops team swarmed the building. She quickly took cover in the corner, cursing the fact her gun was locked in the safe in her office, not that it would have been much use. The combat team surrounded the perpetrator, guns pointed at its chest, but it was strong, stronger than them all combined, they were going to need help.

Sure enough, the swoosh of a cape announced Supergirl's arrival and she drew the attention of the alien, engaging him in a fight.

It didn't take long for Supergirl to subdue him, but not before he threw part of the sign at the agents closing in on him. The sign hit one of the agents, sending her flying to the ground unconscious, her helmet coming loose, showing a deep cut on her forehead… It was Alex.

Lena heard the anguished cry of Supergirl who pummelled the alien in a fit of rage.

Once the alien was secure, Supergirl rushed to Alex, cradling her in her arms, whispering the same thing over and over again. Eventually Lena was able to make out what Supergirl was saying from the spot she had taken cover; _you're going to be fine, you don't get to leave me._

Lena couldn't take it anymore, how was she supposed to compete with the woman who held the affections of both Kara _and_ Supergirl?

Lena began avoiding Kara; she declined interview requests citing she was 'too busy'; she left a note with her secretary to say she was always in a meeting when Kara turned up and she stopped replying to her messages.

Lena had to avoid Kara, seeing her so happy only made her heart break, break at the fact she wasn't the one responsible.

She knew her mother would be disgusted with her behaviour, her words echoed round her head; _jealousy is unbefitting of a Luthor. We are the ones who make the rest of the world jealous of us._ A mantra that refused to leave her alone.

Lena became more of a recluse; a billionaire enigma of National City. When her mother came to town, she wasn't surprised to find Supergirl on her balcony. After all, she _was_ a Luthor.

What she wasn't expecting was the girl of steel to be seemingly nervous to tell her something. Lena had been under the impression they had formed a relatively good working relationship, to the point she could be considered a friend. She also didn't expect to see what could only be described as hurt in the eyes staring back at her.

As she watched, Supergirl fiddled with the sleeve of her suit it all fell into place and Lena's world came crashing down around her. Kara was _Supergirl._ She couldn't breathe; her only two friends in National City were actually the same person; the person she had cut out of her life because she couldn't bear the thought of not being with her, of not being loved by her.

Then the thought hit her- how could Kara ever have loved her? She was a Luthor and Kara was Kryptonian. There was far too much bad blood between their families for a Super and a Luthor to be together.

Lena zoned out, struggling to focus on anything other than the voice in her head telling her no one would ever love her, that she was ridiculous for falling for a Super.

She registered Kara telling her that her mother was running Cadmus, something she had already figured out, but her head was spinning and Kara's voice sounded distant and tinny. She had to get Kara out of her office. She did the only thing that made sense; she lied. Lied like her family had taught her to, to protect herself.

She sneered at Supergirl, the full force of everything she hated about being a Luthor coming to the surface, telling her to get out. How dare she accuse her mother of such a thing, of being the devil incarnate?

She nearly broke down when Kara told her she was too good, too smart to follow in her family's footsteps; and to be her _own_ hero. Her mask wobbled as she watched Supergirl fly away, her body shaking uncontrollably.

Their most recent meeting had been the hardest for Lena; the feeling of her stomach falling though the floor was a familiar occurrence whenever she was around Kara. What nearly forced her to show her hand, to reveal she had double crossed her own mother was the look in Kara's eyes as she pleaded with Lena not to set off the virus, that she was better than this.

Lena knew she had played her role convincingly enough when she saw fear in Kara's eyes, fear that Lena may actually go through with it. It broke Lena's heart to think that Kara thought she was capable of such a thing.

She had tears in her eyes as she turned the key, feeling she had lost Kara forever.

She left after her mother's arrest; Alex had shown up, running towards Kara, she pulled her into a hug and kissed her forehead. Her job was done, she didn't expect any thanks, but a part of her wondered how long it would take Kara to realise that _she_ had been the reason the virus hadn't worked, that _she_ was the one responsible for swapping out the isotope.

She imagined Kara coming to her, thanking her, kissing _her._ But she forced all thoughts from her mind, her fantasy wasn't worth the heartache, so she turned her back on the only friend she had in National City. If she had stayed, she would have seen Alex kissing and linking hands with the detective who had just arrested her mother.

Lena had headed straight back to , nowhere really felt like home and at least there was paperwork to keep her busy. She had contemplated finding a bar, searching for another blonde with blue eyes to keep her company, to make her forget and to loose herself in until she couldn't remember her own name, until she no longer felt this _numb. B_ ut it hadn't worked last time. There was no reason to believe it would work this time.

Back in her office Lena had buried herself in paperwork and scotch, hoping alcohol would help her forget, and to revert to a time before Kara Danvers was in her life. She was desperately hoping to keep the tears that threatened to spill over at bay.

She didn't hear the whoosh of a cape, the clack of heels on concrete or the door to her balcony open. She didn't hear the soft footsteps that came towards her or the heavy breathing of someone who had rushed to her side.

She _did_ hear her name whispered softly, almost like a prayer, uttered from the lips of the caped Superhero she was so desperate to forget.

Lena found that she couldn't hold back her tears any longer; everything her mother had told her was right; she was weak, she would never amount to anything, a Luthor doesn't cry.

She felt strong arms circling her body as Kara pulled her in for a hug, as she rubbed a comforting hand across her back. Lena melted into the embrace, desperate to be close to Kara even as she wanted to forget.

Her anguish quickly turned into anger; she slammed her fist into Supergirl's shoulder and pushed herself away. She couldn't allow herself to get drawn in, _Icarus_ had shown what happened if you flew too close to the sun.

 _NO_ , she had yelled, turning her back to Kara, _you don't get to comfort me, you don't get to carry on as normal, not after leading me to believe that something genuine, something special could have happened between us. Not after flirting with me for months! Letting me fall for you, all the time you have a girlfriend… Kara._ She had spat out the name, turning to see the look of realisation cross Kara's face.

She walked over to her desk and poured herself another scotch, barely registering the words coming out of Kara's mouth, not wanting to listen. She did catch the confused question of _girlfriend? What are you talking about?_

Lena scoffed, her hand tightening around the glass. _Oh don't play dumb_ Lena had sneered, _you and Alex._

Silence filled the air.

Lena just stared at Kara, waiting for some kind of response.

She didn't expect Kara to start laughing.

She froze, rooted to the spot.

 _Present…_

'You think this is some kind of joke?' Lena questioned incredulously.

'I'm so sorry Lena, the situation is so absurd! You seriously think me and Alex are a couple!?' Kara finally managed to say in disbelief.

'Of course you are, I've seen the way you act round her, the way Supergirl acts, you can't deny you are in love' Lena stated sceptically.

'Oh Lena' Kara breathed out, walking towards the shaking woman, 'I love Alex, but not in the way you think.' She reached out to stroke Lena's arm, but retracted when Lena flinched. 'Lena, listen to me, you have this all wrong; Alex is my sister!'

'Your… sister?' Lena stuttered, not quite able to comprehend what Kara was telling her.

'Yes' Kara replied and reached out for Lena's arm again, sighing gratefully when Lena didn't flinch. 'She's always protected me, she helped me learn how to act human when I first came to Earth, we're incredibly close, but she is most definitely _not_ my girlfriend' Kara smiled.

Lena's brow furrowed in confusion, unsure how to process the information.

'Is that why you've been avoiding me?' Kara questioned.

'I thought… When I saw… And then outside… And later… It's just we were getting on so well before…' Lena flustered. She took a deep breath to steady herself and continued 'I really like you Kara… And I couldn't handle it when I thought you were… with… someone else'

Kara slipped her hand into Lena's and slowly rubbed her thumb over Lena's knuckles.

Lena was fighting every instinct in her body to push Kara away; she had a split second to make her decision. She hadn't fully processed anything that had happened that evening; pretending to betray her only friend, lying to her mother, having her mother arrested and the discovery that Alex and Kara were _sisters._

Lena knew what she wanted; she had wanted it ever since she had first seen Alex and Kara walking arm in arm, ever since those first stirrings of jealousy had risen within her.

'Do you feel the same way?' she finally whispered, barely audible, Kara only able to hear due to her super hearing.

Kara just nodded and smiled at Lena.

That was all the confirmation Lena needed; she moved closer to Kara and pressed their lips together.

Lena felt as though she was floating, kissing Kara was unlike anything she had ever imagined. When they finally broke away from the kiss, needing air, Lena realised they were in fact floating, a few inches off the ground. Kara's arms were wrapped around Lena, holding her close, and she felt all the stress and tension draining away… She was home.


End file.
